The present invention generally relates to a copying apparatus particularly, to a copy storing tray for storing supplied copy paper sheets to be refed, etc., such as an intermediate copy tray provided in an automatic duplex copying apparatus.
Conventionally, in an automatic duplex copying apparatus, it has been so arranged that copy paper sheets each having one copied face are temporarily stored in an intermediate copy tray and again delivered from the intermediate copy tray to a copying process portion after exchange of the original document. In a copy storing tray such as the intermediate copy tray for storing the copy paper sheets to be refed, all the supplied copy paper sheets should be accurately stored at a position for storing the copy paper sheets. Meanwhile, in the case where a jam of the copy paper sheets has taken place in the vicinity of the copy storing tray, the jam should be detected immediately so as to be promptly dealt with by the operator.
To this end, in a known intermediate copy tray 73 of FIG. 1, a detection switch 72 for detecting the copy paper sheets is provided in the vicinity of a pair of paper feed rollers 71 for supplying the copy paper sheets to the intermediate copy tray 73 and a detection switch 74, for detecting the copy paper sheets, is mounted on a bottom face of the intermediate copy tray 73. By this arrangement of the known intermediate copy tray 73, jam of the copy paper sheets occurring at a location preceding the paper feeding rollers 71 and jam of the copy paper sheets occurring prior to storage of the copy paper sheets in the intermediate copy tray 73 after the copy paper sheets have been passed through the paper feed rollers 71 are detected. In the known intermediate copy tray, occurrence of the latter jam is determined by detecting that the detection switch 74 is not turned on after the detection switch 72 has been turned off. However, in the known intermediate copy tray 73, in the case where a plurality of the copy paper sheets are continuously supplied to the intermediate copy tray 73, the detection switch 74 is turned on by the first copy paper sheet and is held in the ON state during continuous supply of the subsequent copy paper sheets to the in copy tray 73, regardless of whether or not a jam of the subsequent copy paper sheets has taken place between the paper feed rollers 71 and the intermediate copy tray 73. Thus, at this time, even if a jam of the subsequent copy paper sheets takes place between the paper feeding rollers 71 and the intermediate copy tray 73, the jam is not detected until the detection switch 72 is held in the ON state upon stop of the next copy paper sheet through its collision with the jammed copy paper sheets. Therefore, in the known intermediate copy tray 73, jam of a plurality of the copy paper sheets undesirably takes place due to a delay in the start of the operation for eliminating the jam. Hence, the known intermediate copy tray 73 has such drawbacks that the operation for eliminating the jam becomes complicated and time-consuming and the copying apparatus may be readily damaged by the jam.